I think this might say more about your geographic location than you think :)
People from other continents always surprise me with various fruits they taken for granted their entire life, but I've never heard about, and vice-versa.
Lotus root is pretty common in Chinese and Japanese cuisine. I've had it pickled and in a Sichuan dry pot. It's crunchy and takes on flavors pretty well.
1. Thamarai Thandu Poriyal / Varuval (Stir-fried Lotus Stem): A popular dish where the lotus stem is peeled, sliced into coins, and stir-fried with coconut oil, mustard seeds, shallots, green chilies, curry leaves, and sometimes sambar powder or chili flakes.
2. Thamarai Thandu Uppukari (Lotus Stem Dry Curry): A preparation where the lotus stem is boiled with salt, then deep-fried or stir-fried until light golden brown to create a crispy side dish, often served with rasam rice.
3. Thamarai Kizhangu Vathal (Dried Lotus Root Crisps): A traditional, shelf-stable snack where the lotus stem is sliced, salted, and dried, then fried before consumption.
4. Lotus Petal Paruppu Usili (Steamed Lentil Crumble): A dish made by finely chopping tender inner lotus petals and mixing them with coarsely ground, steamed, and crumbled lentils (dal), similar to traditional Tamil Paruppu Usili.
5. Thamara Vadai (Lotus Stem Fritters): A traditional snack in South India that uses sliced lotus stem in a seasoned batter, similar to a vadai.
Yeah, lotus and ginkgo are both fairly common, I'm sure a lot of us have had them.
Lichen and moss being the most ancient foods makes sense to me based on watching episodes of Alone. You can get calories from that stuff if you're desperate, but it sure doesn't seem a pleasant way to sustain yourself.
Lotus root is pretty common. A crunchy tuber that keeps its texture after cooking, bland taste, unique visual appeal. I threw some in the last pot of bean chili my family made, and the kids liked it.
It's not the sarcotesta, the butyric-acid filled dogshit smelling thing, it's the "seed" (it's not really a seed, morphologically as I understand it...), the sclerotesta that's edible.
Lots of ferns where I live, and I've put fiddleheads in a few stirfries for the novelty of it. But some (bracken especially) are somewhat toxic or carcinogenic. Probably fine if you prepare them properly and don't eat them too often, but be aware.